The continuing objective of this project is to gain information about the ways in which the behavioral effects of drugs depend on the precise details of the control of behavior by the environment. The prime focus is on behavior under control of aversive environmental events, including procedures under which such aversive events serve other than to suppress behavior. Many experiments involve procedures in which behavior is actually maintained by the presentation of intense electric shocks. We are studying the conditions that lead to the development of such seemingly anomolous behavior, and are comparing drug effects on these behaviors with: effects on behavior suppressed by aversive events (punishment), on behavior maintained by the termination or postponement of such events (escape, avoidance), and on responding maintained by presentation of non-aversive events (e.g., food or water presentation. In addition to studying the influence of factors such as a behavior's normal frequency of occurrence and the types of consequent events that maintain it, we are emphasizing study of the role of prior experience and current environmental context as determinants of the behavioral effects of drugs. Dose-effect relations for a variety of classes of drugs (amphetamines, major and minor tranquilizers, antidepressants) will be established. By careful study of the effects of a variety of classes of drugs under a broad range of behavioral procedures, and under different historical and current behavioral contexts, we hope to arrive at generalizations that will prove useful in the rational prediction of drug effects in the clinic.